Process for preparing 3-substituted thiophene

Abstract

The present invention relates to a process for preparing a 3-substituted thiophene represented by the formula (2): wherein R represents a cyano group, a formyl group, a carboxyl group, a hydrocarbyloxycarbonyl group which may have a substituent(s) or an acyl group which may have a substituent(s), which comprises reacting a vinyl compound represented by the formula (1): RCH═CHY  (1) wherein R has the same meaning as defined above, and Y represents a leaving group, and an α-mercaptoacetaldehyde or a multimer thereof.

1 . A process for preparing a 3-substituted thiophene represented by the formula (2): 
     
       
         
         
             
             
         
       
       wherein R represents a cyano group, a formyl group, a carboxyl group, a hydrocarbyloxycarbonyl group which may have a substituent(s) or an acyl group which may have a substituent(s), 
     
     which comprises reacting a vinyl compound represented by the formula (1):
   RCH═CHY  (1) 
 wherein R has the same meaning as defined above, and Y represents a leaving group, and an α-mercaptoacetaldehyde or a multimer thereof. 
 
   
   
       2 . The process for preparing a 3-substituted thiophene according to  claim 1 , wherein the leaving group Y of the vinyl compound represented by the formula (1) is a substituted amino group selected from a monoalkylamino group, monoarylamino group, dialkylamino group and diarylamino group; [NR 1 R 2 R 3 ] + X −  group wherein R 1  to R 3  may be the same or different from each other, and each represent an alkyl group having 1 to 4 carbon atoms, a phenyl group or a benzyl group, and X represents a halogen atom; a halogen atom selected from a fluorine atom, chlorine atom, bromine atom and iodine atom; a substituted thio group selected from an alkylthio group and an arylthio group; an alkylsulfonyl group selected from a mesyl group; an arylsulfonyl group selected from a benzenesulfonyl group and tosyl group; an alkylsulfonyloxyl group selected from a methanesulfonyloxyl group and ethanesulfonyloxyl group; an arylsulfonyloxyl group selected from a benzenesulfonyloxyl group and p-toluenesulfonyloxyl group; an acyloxyl group having 1 to 6 carbon atoms selected from an acetoxyl group, propionyloxyl group and benzoyloxyl group; a hydrocarbyloxyl group which may have a substituent(s). 
   
   
       3 . The process for preparing a 3-substituted thiophene according to  claim 1 , wherein the leaving group Y of the vinyl compound represented by the formula (1) is a dialkylamino group, a diarylamino group, a halogen atom and a hydrocarbyloxyl group which may have a substituent(s). 
   
   
       4 . The process for preparing a 3-substituted thiophene according to  claim 1 , wherein the leaving group Y of the vinyl compound represented by the formula (1) is a dialkylamino group or a hydrocarbyloxyl group which may have a substituent(s). 
   
   
       5 . The process for preparing a 3-substituted thiophene according to  claim 1 , wherein at least one additive selected from the group consisting of an organic base, an inorganic base, a metal alcoholate, an organic acid, a Lewis acid, a mineral acid, a cyclic polyether, a quaternary ammonium salt and a halogenated alkali is presented. 
   
   
       6 . The process for preparing a 3-substituted thiophene according to  claim 1 , wherein at least one additive selected from the group consisting of an organic base, an inorganic base, a metal alcoholate, an organic acid, a Lewis acid, and a mineral acid is presented. 
   
   
       7 . The process for preparing a 3-substituted thiophene according to  claim 5 , wherein an amount of the additive to be used is 0.01 to 10 mols based on 1 mol of the vinyl compound. 
   
   
       8 . The process for preparing a 3-substituted thiophene according to  claim 5 , wherein an amount of the additive to be used is 0.02 to 5 mols based on 1 mol of the vinyl compound. 
   
   
       9 . The process for preparing a 3-substituted thiophene according to  claim 1 , wherein an amount of the α-mercaptoacetaldehyde or a multimer thereof to be used is 0.2 to 20 mols in terms of the α-mercaptoacetaldehyde based on 1 mol of the vinyl compound. 
   
   
       10 . The process for preparing a 3-substituted thiophene according to  claim 1 , wherein an amount of the α-mercaptoacetaldehyde or a multimer thereof to be used is 0.5 to 10 mols in terms of the α-mercaptoacetaldehyde based on 1 mol of the vinyl compound. 
   
   
       11 . The process for preparing a 3-substituted thiophene according to  claim 1 , wherein R is selected from the group consisting of a cyano group, formyl group, methoxycarbonyl group, acetyl group, benzoyl group, valeryl group, octanoyl group, and 2,2-dimethoxy-acetyl group. 
   
   
       12 . The process for preparing a 3-substituted thiophene according to  claim 1 , wherein the reaction is carried out by mixing the vinyl compound, the α-mercaptoacetaldehyde or a multimer thereof, and a solvent, and under stirring at −10 to 200° C. 
   
   
       13 . The process for preparing a 3-substituted thiophene according to  claim 1 , wherein the reaction is carried out by mixing the vinyl compound, the α-mercaptoacetaldehyde or a multimer thereof, and a solvent, and under stirring at 0 to 150° C.